Apparatus for testing filamentary or strip articles



July 1942. E. T. LESSIG 7 2,291,086

APPARATUS FOR TESTING FILAMENTARY QR STRIP ARTICLES Fild Dec. :51, 194040 41 42 35 mu Z9 o 31 J j 27 5 38a .59 A -59 60 Patented July 28, 1942APPARATUS FOR TESTING FILAMENTARY OR STRIP ARTICLES Edward T. Lessig,Silver Lake. Ohio, assignor to The B. F. Goodrich Company, New York, N.Y., a corporation of New York Application December 31, 194o,sena1 No.372,467

4 Claims.

This invention relates to the testing of filamentary or other articlesin flexible strip form,

and especially to apparatus for testing the resistance of such articlesto cyclic bending fatigue.

In selecting material such as cord, wire, etc., suitable for use asreinforcement in tires, transmission belting and the like, orotherflexible strip articles, it is desirable that testing methods andapparatus, adapted to facilitate such selection, set-up a type of stressin the article comparable to the stress or stresses actually to beencountered in the constructions as used. Stresses found in filamentaryarticles when applied totire and transmission belt construction oftenare bending stresses and these are often accompanied by some vibrationeffects.

The chief objects of the present invention are to provide improvedtesting apparatus adapted to subject flexible filamentary or striparticles to cyclic bending stresses, and to provide apparatus forobtaining uniformly accurate and reliable test results on the bendingfatigue of such articles.

A more specific object is to provide testing ap-.

paratus for such articles, comprising one or more. preferably aplurality, of rotatable members upon which the article may be supported,preferably ,by being looped about the members, such members being eachrotatable about its own axis and all being rotatable about a common axisintermediate the members in a manner such that the article so placed issubjected to cyclic bending stresses.

Other objects are to provide means whereby the magnitude of bendingstresses set-up in the article being tested may be varied in line with,the magnitude of the bending stresses to be encountered in the articlewhen in use; to provide for the testing of a plurality of the articlessimultaneously and to provide for ease and convenience of operation andmaintenance.

These and further objects will be apparent from the followingdescription, reference being had to the accompanying drawing in which:

Fig. 1 is a plan ,view of apparatus constructed in accordance with andembodying the invention in its preferred 01m, parts being broken awayand sectioned.

Fig. 2 is a section taken along the line 2-2 of Fig. 1, parts beingbroken away.

Fig. 3 is a view in cross-section of a, modified construction.

Fig. 4 is a view in cross-section of a further modified construction.

Apparatus constructed in accordancelwith the invention is shown in Figs.1 and 2 of the drawing. The apparatus is preferably constructed on asubstantially horizontal table l0 and supported at the desired workingheight by a, frame II and frame supporting members Ila which aredesirably of sufficiently heavy construction to provide adequaterigidity. While the horizontal ar-' rangement is preferred, theapparatusof the invention lends itself to an inclined or even a verticaldisposition, if desired.

A plurality of filamentary articles l2, 12, three in the form of theinvention shown, are secured as by means of independently operated plateclamps l3, l3 mounted on a-supporting post I 4 bolted to the table Hi.The plate clamps i3, I3 may be raised and lowered to engage anddisengage the cord or wire i2, I2 by means of thumb screws l5, l5.Although this clamping means is preferred, because of its convenience,any other suitable means may be used, if desired.

The articles to be tested l2, 12 extend unbrokenly inlooped-aboutrelation over rotatable members which will be more fully describedhereinafter; and over pulleys i6, i6 mounted on a shaft l1 and supportedby a bracket i8 bolted to the table l9. Alternatively, a roller or evensuitable non-rotatable members may be employed in place of the pulleysI6, I B. Weights l9, I9 attached to the test specimens l2, I2 are of amagnitude consistent with the amount of tension desired in the cord orwire l2, l2 being tested. For different tests the tension may be variedbetween a-relatively small amount and the ultimate tensile strength ofthe material being tested.

Intermediate the clamps l3, l3 and the pulleys l6, IS the cords orwires, etc., I2, i2 are looped about a plurality of rollers or otherrotatable members as mentioned hereinabove. The apparatus shown in Figs.1 and 2 comprises two rollrs 20 and 2| rotatably mounted on-shafts 22-and 23 by means of suitable anti-friction bearings as indicated at 24 inconjunction with one end of roller 20 and shaft 22. The shaft 22 and.23are bolted or otherwise secured at each end to vertical plates orspiders 25 and 26 adapted to support the shafts 22 and 23 on the rollers20 and 2| in fixed positons relative to each other. The spiders 25 and26 incorporate sleeves 2i and 28 in which shafts 29 and 30 are keyed,fastened by means of set screws or otherwise secured in non-sliprelation. The shafts 29 and 30, the sleeves 21 and 28 and the spiders 25and 26 are rotatably mounted on suitable anti-friction bearings 3| and32 contained in supporting members '38 and 34 which are bolted to thetable iii. If

desired, a single shaft may be adaptedto extend .hrough both spiders andkeyed to each, or the spiders may be otherwise suitably mountedrotatively.

Any suitable source and may be applied in of power may be utilized theoperation of the apparatus in any manner desired, as for example by themeans shown in Fig. 1 of the drawing. As shown here, power is suppliedby an electric motor 35 by means of sheaves I8 and 38 through atransmission belt 31 to a speed reduction unit indicated generally at39. Power is transmitted from the speed reduction unit 39 throughsheaves 40 and 42 and a belt 4| to the shaft 29. An alternative set ofsheaves 38a and 38a or any suitable combination of sheaves may be usedfor power transmission between the motor 35 and the unit 39' whereby avariety of speeds of rotation may be made available at the testingapparatus.

In the operation of the testing apparatus of the invention, the rollersare revolved about a common axis intermediately of the rollers. Thefilamentary articles being tested are looped about the rollers one ormore times. One turn of the loop as shown in the drawing has been foundsuitable for mostcases. When the rollers are revolved, the portion ofcord or wire looped about the rollers is subjected to bending cyclicallyand adjacent increments" of the cord or wire are bent consecutively andcyclically as, the rollers are revolved. The rollers, being mounted onanti-friction bearings, are rotated by the cord or wire withoutobjectionable slip so that undesirable rubbing between the cord or wireand the rollers and the possibility of wear on the cord or wire isavoided.

Cylindrical rollers, as shown in the form of the invention of thedrawing. provide for substantially uniform bending of the filamentaryarticles being tested. The sharpness of bending may be increased byreducing the diameter of the rollers used, since the curvature of therollers. for a. given arrangement, determines the arc of bending. If atest is desired that subjects the cord or wire to non-uniform bendingother suitable shapes of rollers may be used, as for example rollers ofoval or polygonal shape in crosssection. Also, if a frictional wear testis desired in combination with the cyclic bending test, the rotatablerollers may be replaced with non-rotatable rollers or, other suitablenon-rotatable members without requiring substantial changes in theapparatus as hereinabove described.

- In the bending of the filamentary articles as accomplished by theapparatus of the vinvention, stresses will exist throughout thecross-section of the cord varying in a manner depending upon thelocation of the neutral axis. In a test, therefore, a tendency isinduced in the fibers or particles of the filamentary article to workagainst adjacent fibers or particles and this effect in combination withthe stretching and relaxing of the fibers or particles and their bondsunder the cyclic bending results in conditions of stress and heatingsimilar to those encountered in the cord or wire when applied to certaincons ructions such as tires, belts, etc.

A spring 43 may be suspended between the cord or wire i2, i2 and theweight I9 as shown in Fig. 2 of the drawing, desirably'of such springrate or frequency as to absorb possi le excessive vibration orreciprocating motion in the cord or wire i2. i2 and thereby further addto the peratures are preferably imposed on the filaner such that theportions of the reaches of the articles at the clamps and ing elements45, '45 are preferred and may be ential cyclic bending stressescomprising tensile the cord or wire throughout the heating chamber andthe like, it may be desirable to subject the uniformity and smoothnessof the stresses applied to specimens in a test. I

An insulated heating chamber of any suitable construction, asforfexample the box-like construction 44 as shown in Figs. 1 and 2 ofthe drawing,may be mounted over the rollers in a mannersuch that heatmay be applied about test comparable to. that .existingin structures forwhich the cords or wires are intended. The elevated temmentary articleslocally at the rollers in a manpulleys are not subjected to the elevatedtemperature. Suitable apertures are provided in the side walls of the topermit passage of the articles being tested therethroug'h. Electricalheatdisposed within the heating chamber 44 and connected to a suitablesource of electric current through a rheostat as indicated at 46 in Fig.1.

If it is desired to subject filamentary. articles to more intensivebending stresses, or even compressive stresses, for testing purposes,rollers of relatively small diameter may be used so that the arc ofbending may be sufiiciently small so that the portion on the inner partof the arcs of the bent articles will be compressed periodically.

v A modifiedfo'rm of the invention comprises a pair of relatively smalldiameter roller 50 and 5i disposed as close together as is practicableand mounted on shafts 52 and 53 which may be rotatably mounted inrelatively small bearings 54 and 55 disposed in the spider 56 as shownin Fig. 3 of the drawing. A rod 51 extending between the spiders andsecured by suitable holding means, as for example by set screws as 58,in each spider, may be desirable to supplement the rollers intransmitting rotary motion from. the drive spider to the driven spider.The modified form of apparatus is adapted to subject filamentaryarticles, especially cord, to differstresses in the fibers outwardly inthe cord from the center of the arc of bending and compressive stressesin the fibers of the cord inwardly in the cord toward the center of thearc of bending. By the use of this modified apparatus, tests may be madesimulating differential stresses in cords as they exist in the cords incertain types of structures.

In testing filamentary articles, especially wire wire to a relativelysmall degree of bending. In tests of this type the apparatus of theinvention may be modified by the use of a plurality of rollers, as forexample six rollers as shown in Fig. 4. Rollers 41, 41 are adapted toreceive an article to be tested 48 in looped-about relation and areindependently mounted on anti friction bearings 49, 49 on shafts 50, 50.Th shafts 50, 50 are bolted or otherwise secured to spider 5| rotatablymounted on a shaft 52 an the remainder of the apparatus is substantiallthe same as in the preferred form as herein before described.

The larger number of rollers in this modifica tion provide a reductionin the length of the ar of bending over that of the two roller embodiment inasmuch as the article being tested i here looped about arelatively small portion the circumference of each of six rollers rathparative tests.

than substantially one-halfof the circumference of each of two rollers,and relatively larger diameter rollers are often desirable in thismodiflcation to provide a reduced sharpness in the j are of bending ofthe article being tested.

The elongated rollers of the invention are adapted to receive arelatively large number of test specimens simultaneously in side by sidespaced-apart relation, which results in a substantial saving of time intesting filamentary articles and makes for convenience in making com-Auxiliary means to assist in the rotation of the rollers as they arerevolved about an intermediate axis may be useful in some cases such aswhere metallic articles or a single cord article 1 are being tested.-Such means may, for example, comprise one or more straps, as 59, offabric,

rubber or other suitable material disposed in looped relation about therollers at the end portions thereof in the position indicated at 59 inFig. 1, so as not to interfere with the articles being tested, the endsof such straps. being clamped or otherwise suitably fastened to thetable asshown at 60, 60., ;A tensile force may be applied to the strap59 as, for example, by a spring Bl, shown in Fig. 1, or a suitableweight. Apertares are provided in the walls of the heating chamber topermit passage of the straps therethrough. The disposition of theauxiliary straps, on the roller is similar to that of the articles beingtested.

, The rollers or other rotatable members may be constructed of anysuitable material. Metal such as steel, aluminum, etc., has been foundsuitable for most applications. Where additional friction on the rollersurface is desired, a suitable friction-increasing surface may be added,

in the form, forexample, of fabric, rubber or other suitable compositionor material, to the end that slip between a test specimen and therotatable members will be reduced or eliminated.

While the invention will probably flnd' its most extensive use intesting filamentary articles such as wire. cord andthe like, includingcords of rayon andother material as. well as cotton, the invention isuseful also in the testing of other flexible strip material thanfllamentary articles. for example, strips of fabric rubber,- leather,and other material.

Variations may be made without departing an extensive intermediateportion of said reach in a complete loop about said members, andmeansfor rotating said members as a group spaced-apart axes and mounted forreceiving an extensive intermediate portion of said reach in a completeloop about said members, means for rotating said members as a; groupabout an axis intermediate said spaced-apart axes to flex continuouslythe looped portion of said reach, andmeans disposed at aside of saidmembers opposite to the supporting means for applying substantiallyconstant tension to said reach comprising a weight and a springconnection between said weight and the article.

stresses on flexible filamentary or strip articles 3. Apparatus forimposing cyclic bending substantially without rubbing action on thearticles, for the purpose of testing the resistance of the articles tobending fatigue, said apparatus comprising'means for supporting .reachesof a plurality of thearticles in side-by-side relation, a plurality ofelongated members, anti-friction bearings supporting said members forrotafrom the scope of the invention as it is defined by the followingclaims.

i Iclaim:

1. Apparatus for imposing cyclic bending stresses on a flexiblefilamentary or strip article substantially without rubbing action on thearticle, for the purpose of testing the resistance of the article tobending fatigue, said apparatus comprising means for supporting a reachof the article, means'for applying, tension to said reach,

a plurality of members rotatable about spaced-- apart axes and mountedbetween the supporting tion about spaced-apart axes in a positiontoreceive extensive intermediate portions of said reaches in completeloops about said members, meansjfor rotating'said members as a groupabout an axis intermediate said spaced-apart axes to flex-continuouslythe looped portions of said reaches, and means disposed at a side ofsaid members opposite to. thesupporting means for applying tension tosaid reaches individually. l

4. Apparatus for imposing cyclic bending stresses on'flexiblefilamentary or strip articles substantially without rubbing action onthe articles, for the purpose of testing the resistance of the articlesto bending fatigue, said apparatus I comprising means for clampingthearticles to support a plurality of reaches thereof in sideby-siderelation, a plurality of elongated members, anti-friction bearingssupporting said members for rotation about spaced-apart axes in aposition to receive extensive intermediate portions of said reaches incomplete loops about means and the tensioning means for receiving saidmembers, means for rotating said members as a group about an axisintermediate said spaced-apart axes to flex continuously the loopedportions of said reaches, and means disposed at a side of said membersopposite to the supporting,

means for applying substantially constant tension to said reachescomprising an individual weight for each reach and a' spring connectionbetween each weight and the article.

, 1 EDWARD T. LESSIG

